Upper zone gravel pack



A. D. FLEMING UPPER ZONE GRAVEL PACK July 26, 1966 Filed March 16, 1964AUBREY D. FLEMING.

I NVENTOR.

ATTORNEY.

United States Patent 3,262,499 UPPER ZONE GRAVEL PACK Aubrey D. Fleming,Ozark, Ala., assiguor to Pan American Petroleum Corporation, Tulsa,011111., a corporation of Delaware Filed Mar. 16, 1964, Ser. No. 352,171Claims. (Cl. 166-16) This invention relates to a method and apparatusfor completing a well. More particularly, it relates to dually completedwells with sand entry problems, especially those in which the problem isopposite the upper of two zones.

An object of this invention is to provide a method and apparatus forcontrolling sand entry into a dually completed well especially oppositethe upper of the two zones.

In the drawing FIGURE 1 shows apparatus suitable for excluding sandentry opposite the upper of the two zones in a dually completed well.

FIGURE 2 shows apparatus which can be used to control sand entryopposite the bottom of the two zones if necessary.

Referring to FIGURE 1, well casing 10 extends through producing zones 11and 12. The casing has perforations 13 and 14 opposite zones 11 and 12,respectively. Packer 15 is set in casing 10 between perforations 13 and14. This packer has a large central opening and may be, for example, theone described on page 564 of the Composite Catalog for 1960-61.

Large-diameter tubing section 16 is sealed in the packer by O-ring 17 orother sealing means. Shoulder 18 on tubing section 16 rests on packer 15and supports the large tubing section. A sand screen 19 is attached tothe top of tubing section 16 by means such as collar 26. This may be anyof the cylindrical sand screens, such as slotted or wire-wrappedscreens, known in this art. A tubing seal receptacle 22 is attached tothe bottom of tubing section 16 by means such as collar 23. Above screen19 a long imperforate pipe section'24 extends upwardly. Near the top ofsection 24 is a small section of sand screen 25. This small section ofscreen is used as a tell-tale screen. The top of this screen carriesbackoff threads 26. Preferably, at least a short imperforate pipesection or liner is included between the top of screen 25 and thebackoif threads 26. This prevents spillover of gravel into the liner andprovides more sturdy construc tion for the backoif assembly.

Seated in the tubing seal receptacle 22 is a small-diameter section oftubing 31 carrying O-ring 32 or other sealing means. The top of tubingsection 31 is enlarged to form a shoulder 33 which rests on the inwardlyextending flange 34 of tubing seal receptacle 22 Below tubing section31, and attached to section 31, tailpipe 35 extends to a level nearperforations 14. Above tubing section 31, and attached to this section,is well tubing 36 which extends upwardly through packer 37 to the top ofthe well. Actually, tubing section 31 and tailpipe 35 can be regarded assimply a part of the well tubing string. A second string of well tubing38 also extends through packer 37. Tubing 38, however, extends onlyashort distance below packer 37.

The apparatus is used in a well as follows. First,

' packer 15 is run into the well on an electric cable or other suitablemeans and is set in the casing between the producing zones. The assemblyof large tubing section 16 with sand screen 19 above it and tubing sealreceptacle 22, also attached, is then run intov the well on a workstring (not shown) attached to the assembly by means of backv ofi?threads 26. It will be noted that tubing seal receptacle 22 must bebelow sand screen 19, but may be either above or below large tubingsection 16. Long imperforate pipe 24 and tell-tale screen section 25 maybe omitted in some cases if a long imperforate section is included as apart of screen section 19. Backoif threads 26 will, of course, be placedon the top section of the assembly.

The assembly is run into the well until shoulder 18 comes to rest onpacker 15 and sealing element 17 forms a seal between the packer and theoutside surface of tubing section 16. Gravel is then introduced into thespace outside screen 19 by introducing the gravel into casing 10 butoutside the work string. The gravel is deposited around the screen andpreferably around imperforate pipe section 24 and tell-tale screen 25.The work string is then backed oh and withdrawn from the well.

Next, the assembly of tailpipe 35 and small tubing section 31 on welltubing 36 is run into the well and shoulder 33 on the tubing sectionsets against flange 34 on thetubing seal receptacle. Packer 37 is alsorun into the well on tubing string 36 at the same time. After tubingsection 31 is set in the desired location, packer '37 is set in thecasing.

Finally, tubing string 38 is run into the well and is guided throughpacker 37. The Well can then be produced.

Well fluids produced from zone 12 through perforations 14 can entertubing string 36 through the open bottom of tailpipe 35. Another type ofopening into tubing string 36 below the packer can be used if desired.Well fluids produced from zone 11 through perforations 13 must flow.through the gravel pack in order to reach screen 19. Entry of sand fromzone 11 into the well is thus prevented and a clean oil is producedupwardly through the annular space'between sand screen 19 and tubing 36.The

clean oil enters an opening provided in tubing string 33 and flowsthrough this tubing string to the surface.

In FIGURE 2, casing 10, producing zone 12 and perforations 14 throughcasing 10 opposite zone 12 are as in FIGURE 1. In this case, however,apparatus is shown for use in case zone 12 also produces sand into thewell. The apparatus in this case includes bridging plug 49 set in casing10 below perforations 14. If the bottom of the well is close toperforations 14, the bridging plug will not, of course, be necessary.Shoe 41 rests on bridging plug 40 or the bottom of the well. Above shoe41, sand screen 42'is attached to shoe 41 by means such as collar 43.Near the top of sand screen 42, or an extension of imperforate pipeabove the screen, is centralizer 44 with stop ring '45. Abovecentralizer 44, screen 42 is provided with backoif threads 46.

The apparatus of FIGURE 2 is used as follows. First, bridging plug 40 isrun into the well, if needed. It is run on an electric cable, workstring, or the like and is set in the casing below perforations 14.Screen 42 with shoe 41 and centralizer 44 is then run into the well on awork string (not shown) until shoe 41 comes to rest on bridging plug 49.Gravel is then introduced into the casing, but outside the work string,to fill the space between screen 42 and casing 19. The work string isthen backed off and withdrawn.

The apparatus of FIGURE 1 can then be used, as previously described, tocomplete the well with a gravel pack opposite the upper zone.

It will be apparent that many methods and assemblies of apparatus, asdescribed in the past, can be used in place of the apparatus shown inFIGURE 2 and the method described above to prevent entry of sand intothe well from the lower zone of the well. For example, a screen may beused as a liner without the gravel pack, the screen being set with anupper packer just below backoit threads 46. Many of these methods andsets of apparatus can be used with my method and apparatus for excludingentry of' sand from the upper zone.

A Well in Louisiana was drilled through two sands about 500 feet apart.The well was dually completed without means for excluding sand. Aboutseven months later the well 'went off production because of severe sandproblems in the upper zone. The well was recompleted as a singlecompletion in the lower zone and the well produced for 17 years from thelower zone only. A repair operation was then performed to restore theupper zone to production. During the repair, the upper zone was treatedwith sand and plastic. After six months the upper zone produced enoughsand to plug the tubing. The apparatus shown in FIGURE 1 was then used,as described above, to exclude entry of sand into the well from theupper zone. After almost a year the well is still producing by gas liftwith little, if any, sand entry troubles.

In another well the lower zone was producing some sand. A screen setwith a tubing packer between the casing and screen was sufficient tocontrol sand from this lower zone. Influx of sand from the upper zonewas so severe, however, that extensive workover operations werenecessary to free stuck pipe, rod, and tubing. This well was offproduction for one and a half years because of the sand troubles. Sincethe use of my apparatus and method, however, satisfactory performancehas been maintained for the past six months. This is a pumping well,showing that the apparatus and method are applicable to this type ofwell. In this particular 'well, packer 37, shown in FIGURE 1, wasomitted demonstrating that the packer is not a necessary element of theapparatus.

In still another well, where there was sand trouble from both zones, theapparatus and gravel pack shown in FIGURE 2 was installed opposite thelower zone and the apparatus of FIGURE 1 was used opposite the upperzone. The well has been flowing its full allowable production since thegravel pack was installed without sand troubles.

Many variations of my method and apparatus are possible. For example,centralizers may be, and usually are, used along the imperforate pipesection 24 in FIGURE 1. Packer 37 can be omitted in most cases, asillustrated in one of the examples given above. till other variationsand equivalents will be apparent to those skilled in the art. I do not,therefore, wish to be limited to the specific method and apparatus whichhave been described above by way of example, but only by the followingclaims.

I claim:

1. Apparatus for producing separately formation fluids entering separatesets of perforations in casing in a well in which the upper zoneproduces sand comprising, a packer with a large central opening set inthe casing between said perforations, a large-diameter tubing sectionsealed through said packer, a cylindrical screen attached to the top ofsaid large tubing section, and extending to a level above the top set ofperforations in said casing, a tubing seal receptacle below said screenand attached to said large tubing section, a small tubing string sealedthrough said tubing seal receptacle and extending to the top of thewell, said small tubing having an opening below said tubing sealreceptacle for entry of fluids from the lower set of perforations and agravel pack above said packer between said screen and casing andextending above the top set of perforations in said casing, wherebyfluids from the upper set of perforations flow through said gravel assaid fluids enter the well and flow up said well outside of said smalltubing string.

2. The apparatus of claim 1 including a second small tubing stringextending from the top of said well to a point above said screen, saidsecond string of tubing having an openingfor entry of fluids from theupper set of perforations.

3. The apparatus of claim 1 which includes above said cylindrical stringa long imperforate section of pipe and above said imperforate section atell-tale screen.

4. The apparatus of claim 1 including opposite the lower set ofperforations in said well, and extending above said lower set of saidperforations, a second cylindrical screen and a gravel pack between saidcasing and said second cylindrical screen and extending above said lowerset of perforations.

5. The apparatus of claim 4 which includes above each of saidcylindrical screens a long imperforate section of pipe and above saidpipe a tell-tale screen.

6. A method for producing a well completed in two separate zones byperforating casing opposite said Zones comprising, setting in saidcasing between the two sets of perforations a packer having a largecentral opening, lowering on a work string an assembly including alargediameier tubing section, a cylindrical screen above said largetubing section, and a tubing seal receptacfe below said screen, sealingsaid large tubing section through said packer, introducing gravel aroundsaid screen, detaching said Work string from said assembly, withdrawingsaid work string from the well, runing a tubing string into said welland sealing said tubing string through said tubing seal receptacle,producing fluids from the bottom zone through said tubing string andproducing fluids from the top zone through said gravel pack and screenand up said well outside said tubing string.

7. The method of claim 6 including the steps of running a second tubingstring into said well extending from the top of said well to a pointabove said cylindrical screen and producing said top zone through saidsecond string of tubing.

8. The method of claim 6 in which said assembly includes an imperforatepipe section above said cylindrical section and a tell-tale screen abovesaid imperforate pipe section and in which said gravel is introducedaround said screen until the gravel extends at least to the level ofsaid tell-tale screen.

9. The method of claim 6 in which, before said packer is set, a secondcylindrical screen is set opposite the lower set of perforations andgravel is introduced to fill the space between said casing and secondcylindrical screen to a level above the lower set of perforations.

10. The method. of claim 9 in which each screen has extending above itan imperforate pipe section above which is a tell-tale screen and inwhich gravel is introduced around each screen until the gravel extendsat least to the level of said tell-tale screen.

References Cited by the Examiner UNITED STATES PATENTS 2,597,554 5/1952West 16638 X 2,896,714 7/1959 Killingsworth l6615 2,925,097 2/ 1960Duesterberg l6645 X 3,039,535 6/1962 Hathorn et a1. 16622S 3,149,6719/1964 Alexander 166228 CHARLES E. OCONNELL, Primary Examiner.

J. A, LEPPINK, Assistant Examiner.

1. APPARATUS FOR PRODUCING SEPARATELY FORMATION FLUIDS ENTERINGSEPARATOR SETS OF PERFORATIONS IN CASING IN A WELL IN WHICH THE UPPERZONE PRODUCES AND COMPRISING, A PACKER WITH A LARGE CENTRAL OPENING SETIN THE CASING BETWEEN SAID PERFORATIONS, A LARGE-DIAMETER TUBING SECTIONSEALED THROUGH SAID PACKER, A CYLINDRICAL SCREEN ATTACHED TO THE TOP OFSAID LARGE TUBING SECTION, AND EXTENDING TO A LEVEL ABOVE THE TOP SET OFPERFORATIONS IN SAID CASING A TUBING SEAL RECEPTACLE BELOW SAID SCREENAND ATTACHED TO SAID LARGE TUBING SECTION, A SMALL TUBING STRING SEALEDTHROUGH SAID TUBING SEAL RECEPTACLE AND EXTENDING TO THE TOP OF THEWELL, SAID SMALL TUBING HAVING AN OPENING BELOW SAID TUBING SEALRECEPTACLE FOR ENTRY OF FLUIDS FROM THE LOWER SET OF PERFORATIONS AND AGRAVEL PACK ABOVE SAID PACKER BETWEEN SAID SCREEN AND CASING ANDEXTENDING ABOVE THE TOP SET OF PERFORATIONS IN SAID CASING, WHEREBYFLUIDS FROM THE UPPER SET OF PERFORATIONS FLOW THROUGH SAID GRAVEL ASSAID FLUIDS ENTER THE WELL AND FLOW UP SAID WELL OUTSIDE OF SAID SMALLTUBING STRING.
 6. A METHOD FOR PRODUCING A WELL COMPLETED IN TWOSEPARATE ZONES BY PERFORATING CASING OPPOSITE SAID ZONES COMPRISING,SETTING IN SAID CASING BETWEEN THE TWO SETS OF PERFORATIONS A PACKERHAVING A LARGE CENTRAL OPENING, LOWERING ON A WORK STRING AN ASSEMBLYINCLUDING A LARGEDIAMETER TUBING SECTION, A CYLINDRICAL SCREEN ABOVESAID LARGE TUBING SECTION, AND A TUBING SEAL RECEPTACLE BELOW SAIDSCREEN, SEALING SAID LARGE TUBING SECTION THROUGH SAID PACKER,INTRODUCING GRAVEL AROUND SAID SCREEN, DETACHING SAID WORK STRING FROMSAID ASSEMBLY, WITHDRAWING SAID WORK STRING FROM THE WELL, RUNING ATUBING STRING INTO SAID WELL AND SEALING SAID TUBING STRING THROUGH SAIDTUBING SEAL RECEPTACLE, PRODUCING FLUIDS FROM THE BOTTOM ZONE THROUGHSAID TUBING STRING AND PRODUCING FLUIDS FROM THE TOP ZONE THROUGH SAIDGRAVEL PACK AND SCREEN AND UP SAID WELL OUTSIDE SAID TUBING STRING.